It is the same with our eye glass prescriptions. If the doctor says you need to wear glasses, you get his opinion and prescription and take it to the opticians who provide you with the required prescription glasses. However there are many people who are eager to read and know what actually their vision status is and what power of glasses should be bought, before handing the piece of paper on to the optician.
For these a simple line up of what the prescription would look like. To site an example OS means +1.00 DS; OD is -2.00 - 0.50 x 180; ADD refers to +1.75 OU. Surely a layperson cannot understand what these terms mean. It is understood that Latin abbreviations are used by doctors when writing eye glass prescriptions.
Speaking in Latin terms OD means 'oculus dexter' which refers to the right eye. Oculus sinister or OS means the left eye. If you find OU then your doctor is referring to both your eyes. Now this understood how to decipher the numbers that precede these abbreviations? Simple, here are a few important tips.
Prescription glasses have many numbers by which doctors explain the status of your vision. For instance the starting number for OD is -2.00 referring to farsightedness or nearsightedness; the (-) sign means the powered lens should be negative for nearsightedness. The (+) sign means farsightedness. If the prescription reads as -0.50 it refers to the power between the two eyes that is separated by 90 degrees. The x180 refers to the axis 180 showing the location of the positive meridian of the eye.
Let's take up the rest of the numbers like +1.00 DS. The DS here refers to diopters sphere which means the correction in the left eye is spherical in nature and has no astigmatism. The ADD number +1.75 indicates that a patient requires prescription glasses for close range viewing. This is a situation that is most common at the age of 40 and above.
It should be noted that +1.75 power should not be considered as reading glasses; instead one should do a bit of calculation which would arrive at -0.25 in this way -2.00 +1.75 = 0.25. In this way you would arrive at the result of the right eye being -0.25 -0l50 x 180 and the left eye will have +1.75 +1.00 = +2.75 D.S.
However, just by reading and understanding what these numbers and abbreviations mean does not allow you to use your own decisions in choosing the right prescription glasses. It is always best to follow the doctor's suggestions and buy your glasses from reputed manufacturers or stores either online or may be at your nearest optician that you are familiar with.
With many leading brands in prescription glasses it is always very hard to choose the right one. Whatever may be the design and price the most important factor to consider when buying prescription glasses is the exact power that is prescribed for your type of eye defect. If the power is not perfect then there could be man y side effects like head ache etc. Also beware of fake sellers who have glasses that look attractive but are not meant for wearing without the doctor's prescription.
To learn more about prescription glasses, and how to buy prescription glasses online, please visit: http://www.extraoptical.com